As a wireless cellular network evolves continuously, a next generation mobile communications system not only supports conventional communication, but also supports machine to machine (machine to machine, “M2M” for short) communication, which is also referred to as machine type communication (machine type communication, “MTC” for short). As predicted, in 2020, there will be 50 billion to 100 billion MTC devices connected over a network. This greatly exceeds a current quantity of connections. M2M services are diverse in service types, and different types of M2M services have quite different network requirements. In general, there are several requirements as follows: (I) reliable latency-insensitive transmission; and (II) ultra-reliable and low-latency transmission.
To deal with vast MTC services in a future network and to ensure an ultra-reliable and low-latency service transmission, an uplink grant-free (Grant Free) transmission solution is proposed. The grant-free transmission may be understood as contention-based uplink service data transmission, and is essentially different from data transmission in a wireless local area network (wireless local area network, WLAN) and an existing random access procedure in a Long Term Evolution (LTE, Long Term Evolution) system. However, for grant-free transmission, there is no mechanism that allows a network device to obtain permission to use a grant-free transmission resource.